It has been conventional with this kind of carburetor that a float chamber is provided therein with a float following the liquid level and there is provided above the float a fuel valve arranged to be pushed to closed position by the float upon upward movement thereof. This type of carburetor, however, has the danger that when the carburetor, and accordingly the float chamber which is integral therewith, becomes inclined, for example, on overturning of the vehicle, the float is not always moved upwards and the fuel valve can remain open and the interior fuel can flow out therethrough and result in a fire.